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Quantum Teleportation Sends Information 143 Kilometers
SchrodingerZ writes "Scientists from around the world have collaborated to achieve quantum teleportation over 143 kilometers in free space. Quantum information was sent between the Canary Islands of La Palma and Tenerife. Quantum teleportation is not how it is made out in Star Trek, though. Instead of sending an object (in this case a photon) from one location to another; the information of its quantum state is sent, making a photon on the other end look identical to the original. 'Teleportation across 143 kilometres is a crucial milestone in this research, since that is roughly the minimum distance between the ground and orbiting satellites.' It is the hope of the research team that this experiment will lead to commercial use of quantum teleportation to interact with satellites and ground stations. This will increase the efficiency of satellite communication and help with the expansion of quantum internet usage. The full paper on the experiment can be found [note: abstract only, full article paywalled] in the journal Nature."
So, it's not teleportation. Thanks.
If you are using quantum teleportation, why you even need a satellite???
No. No it wouldn't. Quantum entanglement does not allow for faster than light communication. Common myth.
-- MyLongNickName
It's to provide early warning in the event of a quantum accident - you know something went wrong when the Canaries are both alive and dead.
But it has been mathematically proven that quantum teleportation does not allow faster than light communication. So unless you are not willing to believe mathematical proof, you should believe the previous poster's comment
It's not quite as simple as teleportation, it's just given that name:
https://en.wikipedia.org/wiki/Quantum_teleportation
Most specifically:
"Suppose Alice has a qubit in some arbitrary quantum state
The components of a maximally entangled two-qubit state are distributed to Alice and Bob.
In the end, the qubit in Bob's possession will be in the desired state."
So what Alice is doing is actually modifying the REMOTE qubits to be identical to the LOCAL qubits AFTER the initial information exchange has occurred. You're now literally turning someone's remote blank paper into a copy of the document you have yourself by using a little set of numbers that you determined between yourself last week.
Got a wiki page. It may well be the worst layman's explanation ever :) they got "no-communication" of that theorem just right.
http://en.wikipedia.org/wiki/No-communication_theorem
I've been watching this NOVA series on quantum mechanics - it's been an excellent primer on this stuff for me. It's hosted by Brian Greene, a prof at Columbia who wrote a book about it for a lay audience. I think it would be very approachable for anybody with an interest in science, but without a scientific background.
In the book the The Muppets, they show that frogs can talk and that pigs sometimes become infatuated with them.
I was the AC who posted the first reply. Please read here for more info on why quantum entanglement does not imply FTL communication. http://curious.astro.cornell.edu/question.php?number=612
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
One more thing (dammit Slashdot! Let me edit my damned posts already!!!) --
They just did a new series (the one I linked to above is a little dated - almost 10 years old at this point). You can see that one here. It covers cosmology as well as a bit of quantum mechanics. Still very approachable.
Essentially, the "sender" does not get to choose the message. The sender "observes" the state of a particle with a previously undetermined state. Upon observing the particle, the "sender" causes the particle to have a determined state but does not get to determine what state that paticle is in. The "receivers" particle then has the same state as the "sender's" particle.
So the "sender" doesn't get to choose what message he sends. He simply discovers (bad term, but trying to keep it simple) the state of the particle which becomes the same as what the "receiver" gets. This would not be useful for sending any type of communication.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
The Higgs was not a common myth. It was entirely expected to be there. That's a reason they spent a bazillion dollars on the Large Hadron Collider, because they expected it to be there. Yes, it was possible it wasn't there, but it fit the standard model and so it was like saying, the world could always end tomorrow, but there's no convincing reason to believe it won't be there when the sun comes up.
Quantum teleportation does not transmit information faster than light and it is not expected to. If there was a mechanism that could do that, it would probably get its own article... and a Nobel Prize for whoever figured it out.
It doesn't, that's why you need Scotty to build you a quantum singularity, which allows you to engage the warp nacelles and initiate FTL by sling shotting the message around venus.
Seriously, read a book or something.
Mod me down, my New Earth Global Warmingist friends!
I'll try.
If two events are "time like" then one event occurs before the other *in*all*reference*frames*. i.e. the earlier event could cause the later event. Note that being time like doesn't require the two events to be causally linked but if A causes B then events A and B will be time like
If two events are "space like" then they cannot be causally linked because it is impossible for a signal traveling at the speed of light to get from the first event to the second event in the available time. It also turns out that for space like events different inertial observers don't even agree on which event occurred first. But this causes no problems because events C and D are not causally linked.
If an observer can travel faster than light then the above no longer holds. An observer traveling faster than light will no longer necessarily agree that A happens before B even if A causes B. An appropriate observer can wait for B to happen and then stop A from happening even though it was A that caused B. It is this paradox that leads physicists to assume that faster than light communication is impossible.
The idea of a maximum speed isn't really that crazy anyway. There are only two possible universes, one where there is a maximum speed - which implied time dilation and everything else we see in special relativity - and one where there is no maximum speed - which you get if you take the limit as c approaches infinity in the special relativity equations and turns out to be the newtonian universe. If there is no maximum speed then there is universal time and therefore all events can be uniquely assigned a time and all observers will agree on the ordering.
Tim.
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
It's mathematically proven that if our current understanding of quantum mechanics is correct that quantum teleportation does not allow faster than light communication. That's not the quite the same thing.